For compiling:
* [cmake](https://cmake.org/)
- * [libxml2](http://xmlsoft.org/)
- * a recent C++ compiler
-
-Nominatim comes with its own version of osm2pgsql. See the
-[osm2pgsql README](https://github.com/openstreetmap/osm2pgsql/blob/master/README.md#building)
-for additional dependencies required for compiling osm2pgsql.
-
-For running tests:
-
- * [behave](http://pythonhosted.org/behave/)
- * [Psycopg2](https://initd.org/psycopg)
- * [nose](https://nose.readthedocs.io)
- * [phpunit](https://phpunit.de)
+ * [expat](https://libexpat.github.io/)
+ * [proj](https://proj.org/)
+ * [bzip2](http://www.bzip.org/)
+ * [zlib](https://www.zlib.net/)
+ * [Boost libraries](https://www.boost.org/), including system and filesystem
+ * PostgreSQL client libraries
+ * a recent C++ compiler (gcc 5+ or Clang 3.8+)
For running Nominatim:
- * [PostgreSQL](https://www.postgresql.org) (9.3 or later)
- * [PostGIS](https://postgis.org) (2.2 or later)
+ * [PostgreSQL](https://www.postgresql.org) (9.3 - 11)
+ * [PostGIS](https://postgis.org) (2.2 - 2.5)
+ * [Python 3](https://www.python.org/)
+ * [Psycopg2](https://initd.org/psycopg)
* [PHP](https://php.net) (7.0 or later)
* PHP-pgsql
* PHP-intl (bundled with PHP)
* a webserver (apache or nginx are recommended)
+!!! danger "Important"
+ Postgresql 12+ and Postgis 3.0+ are known to cause performance issues. They are
+ not recommended for a production installation at the moment.
+
For running continuous updates:
* [pyosmium](https://osmcode.org/pyosmium/) (with Python 3)
+For running tests:
+
+ * [behave](http://pythonhosted.org/behave/)
+ * [nose](https://nose.readthedocs.io)
+ * [phpunit](https://phpunit.de)
+
### Hardware
A minimum of 2GB of RAM is required or installation will fail. For a full
means that PostgreSQL needs to run checkpoints less often but it does require
the additional space on your disk.
+Autovacuum must not be switched off because it ensures that the
+tables are frequently analysed. If your machine has very little memory,
+you might consider setting:
+
+ autovacuum_max_workers = 1
+
+and even reduce `autovacuum_work_mem` further. This will reduce the amount
+of memory that autovacuum takes away from the import process.
+
For the initial import, you should also set:
fsync = off
full_page_writes = off
Don't forget to reenable them after the initial import or you risk database
-corruption. Autovacuum must not be switched off because it ensures that the
-tables are frequently analysed.
+corruption.
+
### Webserver setup